Objectives: Application of electron probe and ion probe to the analysis of biological specimens. Major findings: A stage for direct observation of tissue sections and cathode luminescence in the scanning electron microscope has been built and is undergoing final test. Proposed course: 1. In collaboration with the National Bureau of Standards, continue to work out quantitative analytical methods for biology using the electron probe. 2. Apply the scanning electron microscope, with energy dispersive x-ray analytical attachment (EDAX), to the analysis of connective tissues, particularly elastin, and to the analysis of stratified squamous epithelium, squamous carcinomas and basal cell tumors with especial emphasis on sulfur. 3. With Dr. Braylan, study phagocytic activity of mononuclear cell preparations using EDAX to detect the element phagocytized. Correlation of this activity with surface morphology. 4. Use the light microscope stage constructed for the scanning electron microscope in a study of the cathode luminescence of elastic fibers. 5. Construct a light microscope stage for the ETEC scanning electron microscope to be used for energy dispersive x-ray analysis. 6. Apply EDAX analysis to collaborative efforts as they arise.